| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| -7 | Does not apply | 0 |
0%
|
| 0 | No obstacle | 72 |
20.3%
|
| 1 | Minor obstacle | 57 |
16.1%
|
| 2 | Moderate obstacle | 90 |
25.4%
|
| 3 | Major obstacle | 74 |
20.9%
|
| 4 | Very severe obstacle | 61 |
17.2%
|